Accidents: Final Reports - Windshield Strength Cited In Fatal Sikorsky Crash

 - December 29, 2010, 8:44 AM

Sikorsky S-76C++, Morgan City, La., Jan. 4, 2009–While on a Part 135 VFR flight from PHI’s Lake Palourde Heliport to an offshore oil platform, the helicopter crashed into a marsh approximately seven minutes after takeoff, killing the two pilots and six of the seven passengers on board. Data retrieved from the helicopter’s cockpit voice and flight data recorders showed that it was in level flight at 850 feet msl at around 135 knots when a loud “bang” was heard, followed by sounds consistent with rushing wind, engine power reductions and a decrease in rotor speed. The NTSB concluded that the helicopter’s sudden loss of power was caused by the impact of a red-tail hawk that penetrated the windshield near the engine control quadrant, jarred the fire extinguisher T-handles into the engine control levers and pushed the levers toward the flight-idle position. Current regulations for transport-category helicopters include a requirement that, at a minimum, the helicopter should be capable of a safe landing after impact with a 2.2-pound bird at a specific velocity, but FAA requirements for helicopter windshields do not mention bird-strike resistance. According to the NTSB, the helicopter was originally equipped with laminated glass windshields that were eventually replaced by the operator with lighter-weight cast acrylic aftermarket versions, which lacked any bird-strike resistance standards. The Safety Board called on the FAA to develop stricter helicopter windshield bird-strike resistance standards, as well as additional protection for the fire extinguisher T-handles and engine control quadrants for the S-76++ and similarly arranged helicopters; and the installation of audible and visual low-rotor-speed alarm systems, all of which it described as factors contributing to the accident.